Surgical procedures generally involve the preparation of an anatomical site for attachment of an implant or other prosthetic device. Such preparations generally require surgical instrumentation having various components working together to facilitate one or more surgical tasks performed by the surgeon. In many cases, redundant components are necessary to perform the same surgical function for slightly different situations. For instance, a set of like components may be provided in different sizes to accommodate anatomies of different patients. Such redundancies contribute to instrumentation complexity, size, and cost.
Previous efforts have been made to address this problem. For example, surgical instrumentation has been provided with modular components for improved versatility. However, such modularities employ crude locking mechanisms between components which can loosen during the surgical procedure.
In some surgical procedures, measuring devices are provided as part of the surgical instrumentation and are generally used to reference portions of anatomy, locate a surgical instrument with respect to an anatomical landmark, or reposition a first surgical instrument relative to another surgical instrument. Such devices are typically provided as solid, homogeneous, one-piece components configured to be displaced from another component. Such devices are also generally bulky, sit proud in relation to the surgical instruments to which they are attached, and cannot be temporarily adjusted for easy ingress and egress from small surgical sites. Therefore, conventional measuring devices can be difficult or impossible to use with minimally-invasive surgical approaches.
Locking mechanisms which are typical of the prior art utilize setscrews or levers having cam portions, and require a surgeon to constantly re-apply the necessary tightening torques to ensure that components do not loosen during anatomical referencing and other various surgical steps. Loosening of such prior locking mechanisms is common when instrumentation is used in small surgical spaces (i.e., where interference with soft tissue is likely) and in high vibration environments (e.g., when performing surgical steps such as cutting, reaming, pinning, impacting, drilling, and broaching).
Loosening of surgical instrumentation components during a surgical procedure may lead to implant malpositioning, poor implant fit, prolonged surgery time, and adverse patient outcomes. Therefore, there is a need for improved lockable instrument assemblies that allow a surgeon to quickly adjust a first instrumentation component relative to a patient's anatomy or relative to a second instrumentation component. There is also a need for improved lockable instrument assemblies that allow a surgeon to instantaneously lock or unlock first and second instrumentation components together and prevent relative movement therebetween. There is also a need for improved lockable instrument assemblies which are configured to temporarily avoid potential interferences with other surgical instrumentation and portions of anatomy (e.g., soft tissue, cartilage, and bone), particularly in minimally invasive surgical procedures. There is also a need to provide lockable instrument assemblies having improved locking strength characteristics between a first instrumentation component and a second instrumentation component, in order to prevent the first instrumentation component from becoming unintentionally or accidentally unlocked with respect to the second instrumentation component. Additionally, there is a need for improved instrument assemblies which enable surgeons to quickly lock, un-lock, and adjust instrumentation components in different configurations. Moreover, there is a need for improved instrument assemblies which provide a surgeon with tactile feedback and a positive indication that surgical instrumentation components are positively locked together. Lastly, there is a need for improved instrument assemblies which maintain consistent locking forces between components between surgical steps within the same procedure and between different surgical procedures.